The present invention relates to a ribbon lifting mechanism for a typewriter of the type which is so constructed that either of a printing ribbon and correction tape selectively assumes the printing position by the turning of a holder in which both the printing ribbon and correction tape are accommodated.
A typical conventional ribbon lifting mechanism of the above-mentioned type is disclosed in U.S. Pat. No. 4,533,267 and it is constituted by the combination of a holder in which a printing ribbon and correction tape are accommodated one above another, a cam member for displacing the holder up and down with the aid of a cam function, a stopper member adapted to assume the restricting position where an extent of upward displacement of the holder is restricted in order that the printing ribbon is located at the printing position during printing operation and further assume the non-restricting position where an extent of upward displacement of the holder is not restricted in order that the correction tape is located at the printing position during corrective printing operation, and an electromagnet for displacing the stopper member from the restricting position to the non-restricting position.
In the conventional ribbon lifting mechanism the holder is displaced upwardly under the effect of a cam function caused by rotation of the cam member and the printing ribbon assumes the printing position while the stopper member is located at the restricting position due to the electromagnet which fails to be activated, when normal printing operation is performed. On the other hand, when corrective printing operation is performed, the electromagnet is activated and thereby the stopper member is located at the non-restricting position, resulting in an increased extent of upward displacement of the holder. Thus, the correction tape assumes the printing position.
In order that either of the printing ribbon and correction tape selectively assumes the printing position the conventional ribbon lifting mechanism requires special driving elements such as an electromagnet and other elements which serve to displace the stopper member from the restricting position to the non-restricting position. This leads to problems in that the ribbon lifting mechanism is complicated in structure and it is manufactured at an expensive cost.